kitchen sink draining very slowly

[dm59]

I am looking for some helpful ideas. Here is the situation. We've just remodeled our kitchen, which included getting a new sink. The new sink is quite a bit deeper than the old one. In addition, we also installed an RO water system (don't know if that matters). Ever since remodeling, we've been having problems with the sink draining very slowly. Never had this problem before remodeling. I had a professional plumber in (twice), and he used a power snake and a water pressure hose, which helped but only for a couple of weeks. There is also a garbage disposal in the setup, but we had it before remodeling too. We're very careful with what goes down the drain, and almost never use the disposal (there is no need to).

The plumber claims that our drain pipe (which runs about 25 feet from one end of the house to another) must not be pitched enough. We can't see the pipe since it's between the floor and the basement ceiling, but he claims that could be the only reason, and there can't possibly be enough room for a proper pitch for such a long run. In addition, we apparently don't have a proper vent, so we've always (before and after remodeling) had an AAV. (Actually, there is a vent on the roof just above the kitchen, but it appears that it might've been disconnected at some point by previous owners -- is there a way to check that?) It does sound plausible, but the pitch of the pipe was no different before remodeling (we didn't touch it) -- how come it worked fine for years then?

I don't want yet to be opening the basement ceiling to see what's going on with the pipe. Is there anything else that could be done? Any ideas, why after getting a new sink we would be having this problem?

Thanks in advance!

David

 

[Hyper48fan]

Take a picture of the under-sink plumbing, then we can tell you if that's plumbed correctly. It sounds like the deeper sink may have given you some grade issues with the p-trap and continuous waste coming off the waste disposal.

 

[dm59]

Thanks! Here are a couple of different angles.

 

[Hyper48fan]

First, what's draining into the tee on the backside of the AAV? Second, I'm wondering what kind of solvent was used to connect the trap to the waste disposal 90.

 

[dm59]

The RO system is draining behind the AAV. And I'm not sure about the solvent; I think he used some kind of epoxy.

 

[Hyper48fan]

Can you pull the trap and waste disposal 90 off and look inside to see if there is a restriction at that glue joint? Depending on what was used to solvent weld that joint it could have melted the pipe and created a restriction. It's a long shot but it's abnormal so I would like to check that off before you have to get invasive.

 

[dm59]

I don't think there would be a problem with the glue point. This contraption with glue was created just a couple of weeks ago trying to fix the problem. Obviously it hasn't, but it was draining badly before that too.

 

[Hyper48fan]

Check these possibilities off:
1.) Crap in waste disposal or disposal 90.
2.) Restriction in glue joint.
3.) AAV works properly
4.) Trap arm has grade
5.)Vertical portion of drain in wall, behind cabinet is not backed up.

If all of these things can be eliminated then you have grade issues like was suggested or a restriction somewhere in the line. Whatever you do, do not use Draino.

 

[dm59]

Thanks. You mean specifically not to use Drano, or any product like that?

 

[Hyper48fan]

Correct, they will destroy your drainage system. They will also destroy the equipment of the plumber you hire when it doesn't work, and if he's smart he will charge you for it.

 

[LiQuId]

Dont use drano or any product of the likes they will melt your pipes..

if the problem is in deed improper grade of the trap arm then there is little that you can do, I would sugget as mentioned that you make sure that the "cheater vent " AAv is working properly and if it is I would suggest filling both sinks to the top and then draining them both at the same time with the water running... the idea is to create pressure that may clear a blockage ( every foot of water creates .433 psi ) so keeping the level sustained while draining will add pressure to the line... you could also try using a plunger on the line while this drains. I lived in a place where i had to do this every week or the line would slowly choke off. if, after doing this the drain drains normally then you for sure have a grade issue and will have to repeat this process occasionally to keep it clear.

Hope This helps.

 

[JERRYMAC]

from a professional plumber/drainman

do not use any kind of draino products ! !

Do call another ! Different co. Plumber/drain service co.
That can properly clean your drain pipe and you will have many
more years of service from your kitchen drain

i have always as a matter of course power snaked the drains
when doing a remodel because they always seem to clog up
shortly after if not right a way :d

 

[dm59]

Thanks, everyone. I had a plumber come with a camera and it showed really bad clogs in a number of places in the pipe. So, he jetted it, and it as good as new!

Of course, he found another problem. He sent the camera down the main line out of the house and it showed a break about 8-10 feet away from the house with roots going through the line. Past that point the line looks fine, so he's suggesting replacing the 12 (or so) foot section from the house out. The problem is that most of it goes under our front porch (the problem spot is actually 2-3 feet past the porch), so I'm wondering if it would make more sense to just replace the piece of pipe (4-5 feet) where the break is and not to have to dig under the porch.